if they discontinue support for IE6 on Google.com home page, that would really kill off IE6.
I'm sure that some are clicking, but I don't know that IE6 users are necessarily as lucrative to Google as users of other browsers.
In short, IE 6 users are dumber than users of other browsers and Google's revenue is juiced by dumb users who click their ads.
So, if you've got something that says IE 6 users are more likely to click on advertisements than any other version of IE, I'd love to see it - maybe we should still be paying attention to them.
Search is more lowest common denominator, hence it's ongoing compatibility.
Docs needs a heavy amount of JavaScript to do it's work.